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| Home / Outboard Engines / Mercury Engines / Mercury 40 EFI |
Mercury 40 EFI Specifications
The Mercury 40 EFI is a 4-stroke 3-cylinder OHC (overhead camshaft) gasoline outboard engine with a rated power of 40 hp (29.8 kW) at 5750 rpm. The engine cylinder bore is 2.56 in (65.0 mm) and piston stroke is 2.95 in (75.0 mm). A 45.6 cu.in (747 cc) outboard motor has a batch fuel injection system, mechanical fuel pump of diaphragm or plunger type, trochoid pump lubtication system, electric start with bendix starter, and capacitor discharge ignition system. The remote fuel tank capacity is 6.6 gal (25 liters). The propeller is made of aluminum and it has three blades.
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| General Technical Data |
Engine Model ................ Mercury Mariner 40 EFI
Engine Type ................ 4-stroke three-cylinder gasoline outboard engine
Number of Cylinders ................ 3
Displacement, cu.in (cc) ................ 45.6 (747)
Cylinder Bore, in (mm) ................ 2.56 (65.0)
Piston Stroke, in (mm) ................ 2.95 (75.0)
Maximum Engine Power, hp (kW) ................ 40.0 (29.8)
Maximum Engine Speed, rpm ................ 5500-6000
Idle Speed, rpm ................ 775±25
Compression Ratio ................ 9.7:1
Firing Order ................ 1-2-3
Oil Pump Type ................ Trochoid
Engine Oil Pressure, psi (kPa) ................ 30-40 psi (207-278 kPa)
Ignition System ................ Capacitor discharge
Starting System ................ Electric Start
Electrical System Rating, Volts ................ 12
Charging System ................ Alternator
Alternator Rating, Amps ................ 20
Outboard Weight, lbs (kg) ................ 248 (112.7)
| Fuel System |
Fuel System Type ................ Batch fuel injectors
Fuel Pump Type ................ Diaphragm or plunger
Fuel Type ................ Gasoline
Recommended Gasoline ................ Unleaded gasoline (87 octane minimum)
Recommended Oil ................ Quicksilver 4-cycle marine oil
Fuel Pressure (Idle Speed), psi (kPa) ................ 3-6 (21-42)
Fuel Pressure (Wide Open Throttle), psi (kPa) ................ 42-44 (290-303)
| Gear Housing |
Gear Ratio (No Bigfoot) ................ 2.00:1
Gear Ratio (Bigfoot) ................ 2.30:1
Number of Teeth (Forward Gear, No Bigfoot) ................ 26
Number of Teeth (Pinion Gear, No Bigfoot) ................ 13
Number of Teeth (Forward Gear, Bigfoot) ................ 30
Number of Teeth (Pinion Gear, Bigfoot) ................ 13
Pinion Height, in (mm) ................ 0.025 (0.64)
Forward Gear Backlash (No Bigfoot), in (mm) ................ No Adjustment
Forward Gear Backlash (Bigfoot), in (mm) ................ 0.012-0.019 (0.30-0.48)
Water Pressure / RPM, psi (kPa) ................ 12-25 (83-172) / 6000
| Mid Section |
Transom Height (Long Shaft), in (mm) ................ 20 (510)
Full Tilt Up Angle, deg ................ 69
Tilt Pin Adjustment Positions ................ 5+Shallow Water
Steering Pivot Range (Tiller), deg ................ 90
Steering Pivot Range (Remote), deg ................ 60
Allowable Transom Thickness (Max), in (mm) ................ 2.75 (69.8)
| Cylinder Block |
Cylinder Block Type ................ 4-cycle over head camshaft
Cylinder Bore Type ................ Cast iron
Cylinder Compression, psi (kPa) ................ 180-210 (1242-1450)
Cylinder Bore Inside Diameter (Std), in (mm) ................ 2.559 (65.00)
Cylinder Bore Inside Diameter (Max), in (mm) ................ 2.562 (65.08)
Cylinder Bore (Max Out of Round), in (mm) ................ 0.003 (0.076)
Cylinder Bore (Max Taper), in (mm) ................ 0.003 (0.076)
Crankshaft Main Bearing Clearance, in (mm) ................ 0.0005-0.0017 (0.012-0.044)
Crankshart Runout (Maximum), in (mm) ................ 0.0018 (0.046)
Connecting Rod Oil Clearance (Big End), in (mm) ................ 0.0008-0.0020 (0.020-0.052)
Connecting Rod Small End Inside Diameter, in (mm) ................ 0.6293-0.6298 (15.985-15.998)
Piston Type ................ Aluminum
Piston Outside Diameter (Std), in (mm) ................ 2.5570-2.5578 (64.950-64.965)
Piston to Cylinder Clearance, in (mm) ................ 0.0014-0.0026 (0.035-0.065)
Piston Pin Diameter, in (mm) ................ 0.6285-0.6287 (15.965-15.970)
Top Ring End Gap, in (mm) ................ 0.006-0.012 (0.15-0.03)
Middle Ring End Gap, in (mm) ................ 0.012-0.020 (0.30-0.50)
Oil Ring End Gap, in (mm) ................ 0.008-0.028 (0.20-0.70)
Top Ring Side Clearance, in (mm) ................ 0.0008-0.0024 (0.02-0.06)
Middle Ring Side Clearance, in (mm) ................ 0.0008-0.0024 (0.02-0.06)
| Cylinder Head |
Cylinder Head Warp Limit ................ 0.004 (0.10)
Valve Clearance (Intake), in (mm) ................ 0.006-0.010 (0.15-0.25)
Valve Clearance (Exhaust), in (mm) ................ 0.010-0.014 (0.25-0.35)
Valve Head Diameter (Intake), in (mm) ................ 1.256-1.264 (31.9-32.1)
Valve Head Diameter (Exhaust), in (mm) ................ 1.020-1.028 (25.9-26.1)
Valve Face Width (Intake), in (mm) ................ 0.079-0.124 (2.00-3.14)
Valve Face Width (Exhaust), in (mm) ................ 0.079-0.124 (2.00-3.14)
Valve Seat Width (Intake), in (mm) ................ 0.035-0.043 (0.9-1.1)
Valve Seat Width (Exhaust), in (mm) ................ 0.035-0.043 (0.9-1.1)
Valve Stem Outside Diameter (Intake), in (mm) ................ 0.2156-0.2161 (5.475-5.490)
Valve Stem Outside Diameter (Exhaust), in (mm) ................ 0.2150-0.2156 (5.460-5.475)
Valve Guide Inside Diameter (Intake), in (mm) ................ 0.2165-0.2170 (5.500-5.512)
Valve Guide Inside Diameter (Exhaust), in (mm) ................ 0.2165-0.2170 (5.500-5.512)
Valve Stem To Guide Clearance (Intake), in (mm) ................ 0.0004-0.0015 (0.010-0.037)
Valve Stem To Guide Clearance (Exhaust), in (mm) ................ 0.0010-0.0020 (0.025-0.052)
Valve Spring Free Length, in (mm) ................ 1.491-1.569 (37.85-39.85)
Camshaft Bore Inside Diameter, in (mm) ................ 1.4567-1.4577 (37.000-37.025)
| Maintenance Data |
Engine Fuel Type ................ Unleaded 87 octane minimum
Engine Oil Type ................ SAE 10W-30, 25W-40
API Service Classifications ................ SH, SG, SF, CF-4, CE, CD
Engine Oil Capacity, qts (L) ................ 3.15 (3.00)
Lubricant Type ................ Quicksilver gear lube premium blend
Gearcase Capacity (No Bigfoot), qts (L) ................ 0.46 (0.44)
Gearcase Capacity (Bigfoot), qts (L) ................ 0.75 (0.71)
Spark Plug Type ................ Champion RA8HC
Spark Plug Gap, in (mm) ................ 0.040 (1.0)
Ignition Timing (2000 rpm), deg ................ 17 BTDC
Ignition Timing (6000 rpm), deg ................ 28 BTDC
| Service Intervals |
Lubricate all lubrication points ................ Every 100 hours
Change engine oil and replace oil filter ................ Every 100 hours
Inspect and clean spark plugs ................ Every 100 hours
Check engine fuel filter ................ Every 100 hours
Check corrosion control anodes ................ Every 100 hours
Drain and replace gear case lubricant ................ Every 100 hours
Lubricate splines on the drive shaft ................ Every 100 hours
Inspect battery condition ................ Every 100 hours
Check power trim fluid ................ Every 100 hours
Check and adjust valve clearance ................ Every 100 hours
Check engine timing setup ................ Every 100 hours
Check control cable adjustments ................ Every 100 hours
Inspect timing belt ................ Every 100 hours
Replace water pump impeller ................ Every 300 hours
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